A commonly used type of contact terminal comprises a stamped and formed conductive metal box-like socket. Contact terminals of this type are widely used, often in multicontact electrical connectors as well as in connectors containing only one or two terminals.
Contact sockets of this type must be dimensioned such that when the pin is inserted into the socket, a contact force will be exerted by the socket on the pin to form a stable electrical connection between the socket and the pin. However, problems have arisen with the sockets currently available, causing the electrical connection between the socket and the pin to be unreliable and unacceptable.
A major problem associated with the sockets concerns the nonuniformity of manufacture thereof. Generally, the contact areas of the sockets are in the shape of a curved beam. This shape has proven to be difficult to reproduce to the degree of accuracy required to ensure that a positive electrical connection is affected. Consequently, the shape of the contact area may vary from one socket to the next, as well as from one contact area to the next in the same socket. This nonuniformity can lead to many problems, such as excessive wear and poor electrical connection caused by the stubbing of the pin as insertion occurs. These problems, and others, result in the socket being unacceptable.
A second problem with the sockets currently available focuses on insertion problems. The contact areas of the sockets must be able to withstand a great deal of force as the entire contact force exerted on the pin is applied through the contact areas. This requires that the walls of each contact area be strong enough to support the force. However, another criteria of the contact area is that it be as small as possible to minimize the space required by the socket. This is particularly important in this age of miniaturization. Consequently, a balance must be struck in order to obtain the maximum benefits of strength and size. One solution is to provide the contact areas with relatively steep walls to meet the force and size requirements of the socket. Therefore, as insertion occurs, the pin will engage the steep walls, causing the entire insertion force to be abruptly transferred to the pin. The shape of the contact areas can vary greatly, with some surfaces of the contact areas being essentially perpendicular to the sides of the pin. The increase in the insertion force required to overcome this surface can cause the pin to exert harmful forces on an already weak contact area. Also, contact areas can be positioned within given tolerances from the axis of the socket, allowing one or more contact areas to be positioned closer to the axis than the others. Therefore, as the pin is inserted into the socket, the contact areas positioned closest the axis will be contacted first, causing the contact areas closest the axis to wear more readily than the contact areas further from the axis. Each of these problems, when taken alone, can cause harmful effects, however, when combined, serious problems are likely. The chance of stubbing the pin against the contact areas is greatly increased, thereby effectively increasing the insertion force of the pin into the socket. This results in harmful stresses being applied to an already imperfect or weakened contact area which can cause failure of that contact area after only a few cycles.
A third problem with the contact areas of the socket is noticeable when the pin is improperly inserted into the socket. In actual practice, improper orientation is a frequent occurrence. If the pin is inserted at an improper rotation relative to the axis of the socket, the corners of the pin will engage the edges of beams on which the contact areas are located. This is an unwanted result. The corners of the pin are not as highly finished as are the smooth, flat surfaces of the pin, and therefore, the corners are burred and fractured and are usually the location of pin holes in the plating which results in corrosion sites. Consequently, there is no guarantee that the corners will make electrical connection with the edges of the beam when the corners and the edges are engaged. This uncertainty is an unacceptable result for an occurrence which is so frequent.
As is evident, many problems exist with the pin sockets currently available. The present invention teaches of a socket which solves these problems and which ensures that a positive electrical connection will be affected each time the socket is used.